LDR obtains approval in China for their Mobi-C® cervical artificial disc

[cavalier]

LDR obtains approval in China for their Mobi-C® cervical artificial disc

Just thought u might want to know for some of our foreign friends - Jill

[Justin]

Thanks Jill! You're awesome!

[cavalier]

This read is long but I promise if you hang in there reading it - it is a awesome article in comapring the Mobi-C & fusion & talks specifically about risks in the comparisions - it is well written & very easy to understand -
MOBI-C compared to Fusion Study - http://www.pubmedcentral.nih.gov/art...?artid=2588324

J Korean Neurosurg Soc. 2008 October; 44(4): 217–221.
Published online 2008 October 30. doi: 10.3340/jkns.2008.44.4.217.

VERY beigiing of this article states this -
Abstract
Objective
Although anterior cervical discectomy and fusion (ACDF) is the standard treatment for degenerative cervical disc disease, concerns regarding adjacent level degeneration and loss of motion have suggested that arthroplasty may be a better alternative. We have compared clinical and radiological results in patients with cervical disc herniations treated with arthroplasty and ACDF.
Excerpts -
Radiological outcomes
Six months after surgery, cervical lordosis fell from 29.79 to 28.59 in the arthroplasty group and from 24.27 to 17.69 in the fusion group. In the arthroplasty group, lordosis increased during the immediate postoperative period and then decreased to preoperative levels. In the fusion group, however, lordosis decreased gradually, and could not return to preoperative levels
Segmental lordosis changed from 4.78 to 9.32 in the arthroplasty group and fell from 3.93 to 2.82 in the fusion group. Although segmental lordosis in the arthroplasty group maintained more than preoperative levels, the lordosis became a little more kyphotic than before surgery in the fusion group
Upper segmental ROM of the arthroplasty group decreased postoperatively, from 14.42 to 12.58, whereas upper segmental ROM of the fusion group increased, from 10.63 to 11.66 (p>0.05) (Fig. 2C

).
Although lower segmental ROM increased postoperatively in both groups, the increase was higher in the fusion group than in the arthroplasty group (from 10.21 to 11.26 vs. from 11.34 to 11.64, p>0.05) (Fig. 2D

).
Segmental ROM of operative level in arthroplasty group increased postoperatively, although it slightly decreased immediately after surgery, the last ROM was larger than preoperative level (from 12.7 to 15.2) (Fig. 2E
ACDF is currently the most common surgical approach used to treat patients with debilitating cervical degenerative disc disease.3) Although ACDF often provides benefits at the operative level, ACDF-associated adverse effects include adjacent segmental disc disease and limited neck motion. Loss of spinal motion after ACDF is related to additional mechanical stress at adjacent levels, and this stress may initiate or accelerate the degeneration of such levels2,8,11). Nevertheless, the concept of adjacent-segment degeneration remains unproven and the true incidence is controversial issue. However, several studies showed that fusion alters spinal biomechanics7). Increased intradiscal pressure at levels adjacent to intervertebral fusions has been seen in biomechanical modeling of the cervical spine : about 73% and 45% increase in intradiscal pressure at upper and lower levels17). Therefore, there are always the risks of adjacent segment degeneration to be considered due to increase of intradiscal pressure at adjacent levels7). In contrast, arthroplasty of the cervical intervertebral disc, which can maintain the motion by the artificial joint can theoretically prevent degeneration of adjacent spaces.
For arthroplasty, our institute uses Mobi-C®, which is relatively easy to manage, in a procedure similar to that of ACDF. Surgical insertion of Mobi-C® disc prosthesis is very simple, safe, and reproducible, because the implant holder easily allows the adjustment of position, axis and depth6). Thus, the mean operation time was similar in the two groups. We also found that clinical results, as determined by NDI and upper extremity VAS score, were similar in the two groups. Similar results have been reported previously, as has a relationship among symptom improvement and lesion decompression and stabilization9,10). In that study, a significant pain reduction in neck and arm was observed, with no significant differences between both groups. Postoperative recovery, as determined by length of stay in hospital and convalescence time, was significantly better in the arthroplasty group than in the fusion group. We observed no incidence of postoperative orthosis or iliac harvest morbidity in the arthroplasty group, thus shortening postoperative recovery time14,15).
We found that neither postoperative overall cervical lordosis nor segmental lordosis recovered to preoperative levels in the fusion group; rather, these data became more kyphotic. Similarly, a previous study reported that, of 106 patients, 10 (9%) showed cage subsidence in cervical fusion surgery16). Unfortunately, some patients of fusion group, who became more kyphotic, showed cage subsidences after surgery in our study. Other authors have reported that degeneration of adjacent levels was significantly associated with loss of physiological cervical lordosis in a retrospective study of 42 patients followed for a mean of 10 years after undergoing anterior cervical discectomy and fusion for symptomatic cervical lordosis5,7). They also emphasized the importance of the relation between postoperative sagittal alignment and clinical outcomes. We must also consider our procedure didn't use anterior cervical plate. One study reported ACDF with plate could reduce cage subsidence, which might suggest high ratio of kyphosis of our data. However, we thought plate related complications, such as esophageal injury, pulled out screw might be severe problem and clinical outcomes between ACDF with or without anterior plate were not different in one study. Therefore, above results explain the difference of overall and segmental lordosis between two groups in our data were so high and similar clinical outcomes.
One of the primary goals of cervical disc replacement is to reproduce normal kinematics after implantation12). Another study showed the preservation of motion in Bryan® (Medtronic, Tennessee, U.S.A) treated spinal segments17). Our results also showed segmental ROM preservation after surgery.
DISCUSSION
ACDF is currently the most common surgical approach used to treat patients with debilitating cervical degenerative disc disease.3) Although ACDF often provides benefits at the operative level, ACDF-associated adverse effects include adjacent segmental disc disease and limited neck motion. Loss of spinal motion after ACDF is related to additional mechanical stress at adjacent levels, and this stress may initiate or accelerate the degeneration of such levels2,8,11). Nevertheless, the concept of adjacent-segment degeneration remains unproven and the true incidence is controversial issue. However, several studies showed that fusion alters spinal biomechanics7). Increased intradiscal pressure at levels adjacent to intervertebral fusions has been seen in biomechanical modeling of the cervical spine : about 73% and 45% increase in intradiscal pressure at upper and lower levels17). Therefore, there are always the risks of adjacent segment degeneration to be considered due to increase of intradiscal pressure at adjacent levels7). In contrast, arthroplasty of the cervical intervertebral disc, which can maintain the motion by the artificial joint can theoretically prevent degeneration of adjacent spaces.
For arthroplasty, our institute uses Mobi-C®, which is relatively easy to manage, in a procedure similar to that of ACDF. Surgical insertion of Mobi-C® disc prosthesis is very simple, safe, and reproducible, because the implant holder easily allows the adjustment of position, axis and depth6). Thus, the mean operation time was similar in the two groups. We also found that clinical results, as determined by NDI and upper extremity VAS score, were similar in the two groups. Similar results have been reported previously, as has a relationship among symptom improvement and lesion decompression and stabilization9,10). In that study, a significant pain reduction in neck and arm was observed, with no significant differences between both groups. Postoperative recovery, as determined by length of stay in hospital and convalescence time, was significantly better in the arthroplasty group than in the fusion group. We observed no incidence of postoperative orthosis or iliac harvest morbidity in the arthroplasty group, thus shortening postoperative recovery time14,15).
We found that neither postoperative overall cervical lordosis nor segmental lordosis recovered to preoperative levels in the fusion group; rather, these data became more kyphotic. Similarly, a previous study reported that, of 106 patients, 10 (9%) showed cage subsidence in cervical fusion surgery16). Unfortunately, some patients of fusion group, who became more kyphotic, showed cage subsidences after surgery in our study. Other authors have reported that degeneration of adjacent levels was significantly associated with loss of physiological cervical lordosis in a retrospective study of 42 patients followed for a mean of 10 years after undergoing anterior cervical discectomy and fusion for symptomatic cervical lordosis5,7). They also emphasized the importance of the relation between postoperative sagittal alignment and clinical outcomes. We must also consider our procedure didn't use anterior cervical plate. One study reported ACDF with plate could reduce cage subsidence, which might suggest high ratio of kyphosis of our data. However, we thought plate related complications, such as esophageal injury, pulled out screw might be severe problem and clinical outcomes between ACDF with or without anterior plate were not different in one study. Therefore, above results explain the difference of overall and segmental lordosis between two groups in our data were so high and similar clinical outcomes.
One of the primary goals of cervical disc replacement is to reproduce normal kinematics after implantation12). Another study showed the preservation of motion in Bryan® (Medtronic, Tennessee, U.S.A) treated spinal segments17). Our results also showed segmental ROM preservation after surgery.
We found that adjacent upper segmental ROM decreased in the arthroplasty group, but increased in the fusion group. Similarly, the increase in lower segmental ROM was greater in the fusion group than in the arthroplasty group. Taken together, these findings indicate that, compared with fusion, arthroplasty has the advantage of preventing hypermobility of adjacent segments. Similarly, other studies have shown that motion of the treated level maintained at preoperative levels in patients who underwent arthroplasty, indicating that this form of surgery did not affect the motion of adjacent levels9,10,12,18).
CONCLUSION
Clinical results, such as NDI and upper extremity VAS score, were similar in both groups that underwent arthroplasty or fusion. Postoperative recovery time was, however, shorter in the arthroplasty group, which may be related to absence of postoperative orthosis and iliac graft donor site pain. Patients in the fusion group tended to become more kyphotic than before surgery, which may be related to postoperative graft subsidence in some cases. Although statistically not significant, ROM of adjacent segments was smaller in the arthroplasty than in the fusion group. And, ROM of the operative level in the arthroplasty group was preserved. However, our study has limitation of short follow up and small number of patients. More cases and long-term follow up are needed to make conclusion about the efficacy of cervical arthroplasty.

NOW IF the FDA would get caught up to other countries & approve this device it appears to be a good one - Jill